Note 2 - Securities - Securities in a Continuous Loss Position (Details) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Securities available for sale, continuous unrealized loss position, less than 12 months	$ 351,062,000	$ 119,073,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	6,455,000	899,000
Securities available for sale, continuous unrealized loss position, 12 months or more	110,491,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	3,503,000	0
Securities available for sale, continuous unrealized loss position	461,553,000	119,073,000
Securities available for sale, continuous unrealized loss position, unrealized loss	9,958,000	899,000
US Government Agencies Debt Securities [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	274,287,000	118,650,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	5,274,000	897,000
Securities available for sale, continuous unrealized loss position, 12 months or more	110,053,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	3,495,000	0
Securities available for sale, continuous unrealized loss position	384,340,000	118,650,000
Securities available for sale, continuous unrealized loss position, unrealized loss	8,769,000	897,000
Collateralized Mortgage Backed Securities [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	23,184,000	0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	652,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more	24,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	0	0
Securities available for sale, continuous unrealized loss position	23,208,000	0
Securities available for sale, continuous unrealized loss position, unrealized loss	652,000	0
Municipal General Obligation Bonds [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	40,748,000	0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	392,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more	0	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	0	0
Securities available for sale, continuous unrealized loss position	40,748,000	0
Securities available for sale, continuous unrealized loss position, unrealized loss	392,000	0
Municipal Revenue Bonds [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	12,843,000	423,000
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	137,000	2,000
Securities available for sale, continuous unrealized loss position, 12 months or more	414,000	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	8,000	0
Securities available for sale, continuous unrealized loss position	13,257,000	423,000
Securities available for sale, continuous unrealized loss position, unrealized loss	145,000	2,000
Other Debt and Equity Securities [Member]
Securities available for sale, continuous unrealized loss position, less than 12 months	0	0
Securities available for sale, continuous unrealized loss position, less than 12 months, unrealized loss	0	0
Securities available for sale, continuous unrealized loss position, 12 months or more	0	0
Securities available for sale, continuous unrealized loss position, 12 months or more, unrealized loss	0	0
Securities available for sale, continuous unrealized loss position	0	0
Securities available for sale, continuous unrealized loss position, unrealized loss	$ 0	$ 0